Differential feeding mechanism



A- H. DE VOE.

DIFFERENTIAL FEEDING MECHANISM.

Ar rucmou FILED 11m: I0. I9l6.

1,313,524. Patented Aug. 19, 1919.

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x \I Q WITNESS \1 INVENTIOR I t I ATTORNEY A. H..DE v05. DIFFERENTIAL FEEDING MECHANISM.

' APPLICATION FILED JUNE 10. I916.

1,313,524. r v PatentedAug. 19,1919.

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DIFFERENTIAL FEEDING MECHANISM.

APPLICATION FILED JUNE 10- I916.

1,313,524, Patented Aug. 19, 1919.

3 SHEETS-SHEET 3. 19

1.9 a A a: g .4 12 il I t lg"? 54' :J 33 1. Z2 2r 6 7 UNITED STATES OFFICE.

ALBERT H. DE VOE, 0F WESTFIELD, NEW JERSEY, ASSIGNOR TO THE SINGER MANU- FACTURIN G COMPANY, A CORPORATION OF NEW JERSEY.

* DIFFERENTIAL FEEDING Specification of Letters Patent.

Application filed June 10. 1916. Serial No. 102.851.

West-field, in the-county of Union and State of New Jersey, haveinvented certain new and useful Improvements in Differentla-l Feeding Mechanisms, of which the following-is a specification, reference being had therein to the accompanying drawings.

This invention relates to that class of differential feeding mechanism for sewing machines in which two differentially actuand return-movements of substantially equal amplitude, the rising-and-falling movements being so timed that one of the feeddogs is maintained elevated above the surj ects will appear from the following'descrip face of the work-plate for a longer period of time during its feeding stroke than the other feed-dog.

One of the objects of the invention 1s .to provide a simple, durable and effective differential feeding-mechanism particularly for th'at class of sewing machines having a rotary shaft below the work-plate although adapted for machines of other types. An-

other object of the invention is to provide a manual control for readily changing the feeding action of the improved mechanism Without stopping the machine. Other o'btion and claims.

According to the present improvement in its preferred embodiment, two feed-levers or bars, extending in the same general direction and each carrying a feed-dog, are pivoted at one end to a rocking frame to which feed-- and return-movements are imparted through a sliding pin-and-socket connection with a strap embracing an adjustable eccentric mounted on the looper actuating shaft.

Rising-and-falling movements are given to the primary feed-lever throughanother pinand-socket connection with a strap embracing another eccentric -on the looper-shaft.

Rising-and-falling movements are imparted to the secondary feed-lever from the primary lever through an intermediate rocking element or dilferentiator pivoted to the primary feed-lever and connected to the frame through a link. An adjustable pin, carried by and movable lengthwise of the secondary lever, enters a slot in the difi'erentiator which acts to raise and lower the secondary lever relative to the primary lever and difi'erentiate the rising-and-falling movements of I mechanism shown in Fig. 1 at the same ated' feed-dogs are given synchronous feed- ;Fig.;.3 is a planview. Fig. 4 is a rear elevaperibd in the cycle of feeding movements.

ti'ono'if the feeding-mechanism. Figs. 5 and 6 illustrate different relative positions assumed by the elements of the feeding-mechathelsecoridary lever in one of its extreme Fig. 8 is a plan positions of adjustment.

Fig. 9

view of, the secondary feed-lever.

. Patented Aug. 19, 19119.

is a plan view of the primary feed-lever, 5

and Fig. 10 is a section on the line 1010,

Fig. 1.

The present improvement is a development of the feeding-mechanism disclosed in my copending application Serial 'No. 85,535, filed May 21, 1916, and in'its preferred embodiment is shown applied to a flat bed machine having a base 1 and an elevated clothplate 7) between which and the base is journ-aled the looper actuating shaft 3 having the reduced forward end-portion 4. The primary feed-dog 5, which in the present embodiment may also be termed the auxiliary or fulling feed-dog, is provided with a downwardly extended shank 6 having a slot 6 entered by a screw 6" shank 6 .in adjusted position in a seat provided therefor in the head 7 of a slotted cross-bar 8 secured by the screw 9 to the seat 10 formed in the upper front end portion of the primary feed-lever 11, the rearward end of which is extended laterally, as shown in Fig. 9, and provided with spaced tubular bosses 12, 12 which are freely entered by the pin 13 journaled in spaced tubular bosses 14 14 projecting upwardly from the H-shaped rocking frame 15 having lower spaced tubular bosses 16, 16, within which is fixedly secured the shaft 17 journaled in bushings 18, 18 fitted within suitable apertures provided therefor in the frame. I

The primary feed-lever 11 has depending adapted to hold the i therefrom a tubular boss 19 affording a I socket in which is slidingly fitted a pin 20' projecting laterally from a strap 21 embracing-the feed-lifting eccentric 22 fixed upon the reduced portion 4 of the shaft 3.

The rockingframe 15 is provided with the lateral arm 23 formed at its end with the tubular boss 24 within which is fixedly secured the eccentric shank'25", Fig. 2, of a pin 25 which freely enters a socket afi'orded D 35 and the prlmary and secondary feedby a tulbu-lar boss 26 formed on the eccentric strap 27 which embraces the feed actuating eccentric 28 ad-justably mounted, in a manner well-known, on the shaft 3-.

T The secondary feed-dog 29, which in the present instance is the main feed-dog, has a shank 30 seated in the. enlarged free end of the secondary feedlever 31 extending alongside the primary feed-lever 11 and having near its rearward-end a transverse tubular boss 32 fixedly secured to the pin 13 ina position intermediate the spaced bosses 12 onthe primary feed-lever. a The rising-and-falling movements .im-

parted to the primary feed-lever are trans-.

mitted to the secondary feed-lever, and the feedand return-movements of the primary lever are utilized to differentiate the risingand-falling movements of the secondary feed-lever'relative to the primary feed-lever,

through the following connections: J ournaled in a tubular boss 33 formed transversely and intermediate the ends of the primary feed-lever 11, is the pivot-pin 34 extending'laterally from one side face of a rocking difl erentiator 35 formed with a depending arm 36 connected by a screw-pin to one end of a link 37 whose opposite end is pivotally connected to the top of a post 38 fixed to the base 1.- The difierentiator 35 is formed with a substantially horizontally extending slot 39, shown in the cross-section in Fig. 10, in which is slidingly fitted the rectangular block 40 loosely mounted on the pin 41 projecting, through a slot 42 in the secondary feed-lever, from a slide-plate 43 let into a longitudinally extending recess 44 in the outer side face of the secondary feedlever and suitably held in position in said recess by a screw 45 which extends through a slot 46 in the slide-plate'and is threaded into the secondary'feed-lever.

Provision is made for adjusting the slideplate 43 longitudinally of the-recess44 without stopping the machine. The screw 47 carried by the slide-plate 43 is embraced by the forked extremity of a bellcrank-lever 48 pivoted to the secondary feed-lever by a slot 51 formed in the downwardly extended rear end of the secondary feed-lever 31 and adapted to hold the bellcrank-lever in adjusted position if tightened.-

levers are so proportioned that when the bellcrank-lever is at. one extremity of its movement the pin 41 and pivot-pin 34 are in axial alinement. In this position of theparts the differentiator 35 is ineffective and the primary and secondary feed-levers move together as one.

I prefer to employ a resser-foot having independently movable sole portions 54 and 55. The forwardly disposed sole portion 54 is pivotally connected at 56 to abar 57 pivoted at 58 to the rearwardly disposed sole portion 55. A spring 59 serves to yieldingly depress the bar 57 carrying the sole portion 54. The rearwardly disposed sole portion 55 is carried by the usual springpressed presser-bar 66.

In the operation of the mechanism, with the parts in the position shown. in Figs. 1 and 2, as the shaft 3 turns in the direction of the arrow, the feed-dogs begin to rise.

from their lowest positions. At the same time the eccentric 28 rocks the frame 15 to the left in Fig. 2, which imparts return movements to the feed-dogs.

At this time the primary feed-dog. 5' extends slightly.

higher than the feed-dog 29 but as said levers are moved toward the position shown in Fig. 5, the difl'erentiator 35 is tilted and acts as a lever to lift the pin 41.sufiiciently Ito raise the feed-dog 29 substantially to the level of the feed-dog 5, in which relative positions the feed-dogs are lifted above the surface of the work-plate p by the action of the lifting eccentric 22 and moved to the position shown in Fig; 5.

As the feed-dogs are moved in the direction of feed, from the position shown in Fig. '5 to that shown in Fig. 6, the diflerentiator 35 is tilted rearwardly and acts to lower the pin 41 relative to the pin 34 thus lowering the feed-dog 29 below the surface of the work-support 72 before the feed-dog 5 has finished its feeding stroke. As a result of this actionth'e rearward sole" portion 55 will hold the portion of the work advanced by the feedrdog 29 against the throat-plate 1 while the forward feed-dog 5, in finishing its feeding stroke, will crowd or-full in the material to a certain extent. The relative positions occupied by the feeddogs 5 .and29, one forwardly of the other,

may obviously be reversed, thereby produc-- ing a stretching feed;

lVhile I have shown and described the preferred embodiment of the invention, I realize that it is susceptible of considerable modification in the construction and arrangement of the various parts, within the scope of the invention.

Havingthus set forth the nature of the invention, what Iclaim herein is 1. Differential feeding' mechanism for sewing machines comprising, in combination, primary and secondary feed-dogs, primary and secondary levers supporting said feed-dogs, respectively, a pivotal connection between said levers, means independent of said pivotal connection whereby endwise movements derived from one of said levers are converted into differential rising-and falling movements of the other lever, and annually controlled means for varying the action of said first mentioned means While the machine is in operation.

2. Differential feeding mechanism for sewing machines comprising, in combination, a main-shaft, primary and secondary feed-dogs, pivotally connected primary and secondary levers supporting said feed-dogs, respectively, means connected to the mainshaft for imparting rising-and-falling and endwise feedin movements to said levers, means independent of said pivotal connec tion whereby endwise movements of said primar lever are utilized to differentiate the ris1ng-and-falling movements of one of said levers relative to the other, and man- 7 ually controlled means for varying the action of said last-mentioned means while the machine is in operation.

3. Differential feeding mechanism for sewing machines comprising, in combination, a rocking and endwise movable primary lever carrying a feed-dog, actuating means therefor, a secondary lever pivoted to said primary lever and carrying another feed-dog, adjustable means comprising a difl'erentiator carried by said primary lever for imparting differential tilting movements to said secondary lever relative to said primary lever, whereby differential feeding actions are imparted to said dogs, and a manually controlled device for adjusting said adjustable means Without stopping the machine.

4. Differential feeding mechanism for sewing machines comprlsing, in combination, a rocking and endwise movable primary lever carrying a feed-dog, actuating means therefor, a secondary lever connected to said primary lever and carrying another feed-dog, adjustable means comprising an element carried by said primary lever and anchored to the frame for imparting differential rocking movements to said secondary lever relative to said primary lever, Whereby differential feeding actions are imparted to said feed-dogs, and a manually controlled endwise feeding movements of equal amplitude to said levers, means for lmparting rising-and-fa-lling movements to said levers including adjustable differentiating means for transmitting the rising-andfalling movements of one lever to the other, and manually controlled means for adjusting said adjustable means without stopping the machine.

6. Differential feeding mechanism for sewing machines comprising, in combination, a frame, primary and secondary levers, feed-dogs actuated thereby, a movable supporting element to which said levers are pivotally connected, a differentiator pivotally connected to one of said levers and anchored to the frame, an adjustable connection between said difleren-tiator and the other of said levers and manually controlled means for adjusting said connection without stopping the machine.

7. Differential feeding. mechanism for sewing machines comprising, in combination, pivotally mounted primary and secondary feed-levers, means for imparting rising-and-falling and simultaneous feedand return movements to said levers, means carried by said feed-levers for differentiating the rising-and-falling movements thereing rising-and-falling movements to said primary lever, a slotted differentiator piv-- otally mounted on saidprimary lever, a link connection between said difier'entiator and of, and a manually controlled lever pivotally said main-frame, and a pin adjustably mounted on said secondary lever and entering the slot in said difierentiator.

9. Differential feeding mechanism for sewing machines comprising, in combination, a main frame, a rocking frame pivoted to said main frame, primary and secondary levers pivoted to said rocking frame and each carrying a feed-dog, means for imparting rising-and-falling movements to said primary lever, a slotted differentiator pivotally mounted on said primary lever, a link connection between said difi'erentiator and said main frame, a pin adjustably mounted on said secondary lever and entering the slot in said differentiator, and a manually controlled device carrled by said secondary lever and adapted to permit adjustments of said pin without stopping the machine.

10. Differential feeding mechanism I for sewing machines comprising,- a rocking and" by said primary lever for imparting difierential feed movements to said secondary 10 lever relatively to said primary lever, and a' treadle-controlled device for effecting the desired adjustment of the feed difi'erentiatmg means.

In testimony whereof, I have signed my 15 I name to this specification.

ALBERT H. DE VOE. 

